1. Field of the Invention
The invention relates in general to a circuit and a method for decoding color codes of a 3D video signal. More particularly, the invention relates to a method and a circuit built into an on screen display unit in a display to decode a 3D video signal into a color code.
2. Description of the Related Art
One of the objectives of developing technology is to improve living quality. As technology continuously progresses, living quality is constantly enhanced. For example, in audio video systems, the planar (2D) image has now advanced to a 3D (stereo) image with a bodily experience.
FIG. 1 shows a schematic drawing of a 3D color code. In FIG. 1, a vertical synchronous signal with first 64 lines of horizontal synchronous signals of a 3D image is shown. The color code signal is a signal to distinguish a 3D image format in a 3D stereo video system (not shown). The signal is normally hidden in a video graphics adapter (VGA) signal. By mapping the red (R) signal, green (G) signal and blue (B) signal, the color code hidden in the video signal can be detected. The display then processes properly according to the image format.
FIG. 2 shows a schematic drawing of a 3D video system. In FIG. 2, the conventional decoding method of a 3D video color code is to output a 3D video signal in a video signal from a VGA card 204 of a computer 202. Via a cable 206, the 3D video signal is then sent to a signal processing box 208 with a 3D video color code decoding and signal processing circuit. The 3D video color decoded circuit in the signal processing box 208 detects the color code signal and determines the type of the 3D video signal (the currently used 3D video signal format includes Sync Double, Line Blinking, Page Flipping and Interleave) for proper video signal process.
After being decoded and processed by the signal processing box 208, the 3D video signal is sent to the display 210 to display a 3D video image. The wireless eradiation device 212 transmits the 3D synchronous signal in a form of an electric wave to a pair of 3D glasses. The observer can thus have a 3D vision by alternately blocking one eye.
FIG. 3 is a block diagram showing a conventional 3D video color code decoded and signal processed circuit. In FIG. 3, the comparator 302 compares the level of R signal of the RGB signal output from a VGA card. The comparison result is output to a micro-controller 310 as color code decoding data. Similarly, the comparators 304 and 306 compare the levels of G and B signals of the RGB signal, respectively, as color code decoding data, which are then output to the micro-controller 310.
The horizontal and vertical synchronous signals output from the VGA card are used for circuit synchronization of the micro-controller 310 and the display (not shown). The micro-controller 310 generates a 3D synchronous signal, which is then sent to a pair of 3D glasses, according to the horizontal and vertical synchronous signals. The blocking speed of the 3D glasses is thus synchronous to the 3D video image shown by the display. The micro-controller 310 further comprises a function of processing signal. When the micro-controller 310 receives the color code decoding data from the comparators 302, 304 and 306, the type of the 3D video signal is determined according to the built-in 3D video signal format data. A proper image signal process is then performed.
Accordingly, the conventional color code decoding system is of a 3D display is installed in an external signal processing box. The signal processing box is connected to the VGA card of computer via a cable. The color code decoding system of the 3D display receives an image signal output from the VGA card. Thus, a decoding device (typically a micro-controller) is required between the computer and the display to decode the 3D video signal. This is very inconvenient and not economic at all.